The lead pilot of two US planes which crashed into a mountain was entirely to blame for the accident, a court martial has heard.

Closing the case for the defence, Michael Jones QC said the RAF air traffic controller accused of causing the deaths had breached no regulations.

Mr Jones questioned the justice of Flight Lieutenant Malcolm Williams being found guilty of a crime.

He also questioned the strength of the prosecution's case, which he said had changed since the start of the hearing.

Mr Williams, 47, of RAF Leuchars, Fife, is charged with causing the deaths of Lieutenant Colonel Kenneth Hyvonen, 40, and Captain Kirk Jones, 27, who were both based at RAF Lakenheath in Suffolk.

It is alleged that Mr Williams told the Americans to fly below 6,500ft when they requested the "minimum vectoring altitude".

He mistook the snow as white sky underneath and beyond that cloud and flew on into the mountain

Michael JonesDefence QC

The two pilots died when their F15s crashed into Ben Macdui in the Cairngorms during a snowstorm on 26 March, 2001.

Appearing before the court martial in Helensburgh, Argyll and Bute, Mr Williams denies the charge and an alternative charge of professional negligence.

Mr Jones told the court that Mr Williams had not broken any rules on the day of the crash.

"In the factual context of this case the entire responsibility lies with Lieutenant Colonel Hyvonen (the lead pilot) when we are looking at this viewed through the eyes of an air
traffic controller," he said.

"The pilot was wholly responsible for terrain clearance.

"He mistook the snow as white sky underneath and beyond that cloud and flew on into the mountain."